The field of the invention is irrigation valve control.
Most conventional irrigation systems comprise: an irrigation controller; solenoids that are activated by the irrigation controller; valves that are opened and closed by the solenoids; and sprinkler heads or other types of water distribution apparatus for applying water to a landscape when the valves are open. Wires run from the irrigation controller to the solenoid/valve units. With early irrigation systems, there was a separate set of wires running to each solenoid/valve unit. One line is for delivering low voltage power and the second line is the common return line to complete the circuit. Additionally, another set of wires went from the irrigation controller to the solenoid/valve unit for controlling the opening and closing of the valves. With irrigation systems that have several valves or when valves are placed over a wide area, as with some large golf courses, public parks, etc. it may be quite expensive to install two sets of wires to each solenoid/valve unit
Today there are known irrigation systems that use one set of wires, one set of wires plus a third wire, or two sets of wires from the irrigation controller to connect to all of the solenoid/valve units. Generally a coded control message is sent over the wire to the solenoid/valve units. Each solenoid/valve unit has a decoding mechanism that can decode the coded control message to affect the opening and closing of the valves. Some known irrigation systems send the encoded control message over the power line wires and others have separate wires for transmission of the encoded control message. Irrigation systems such as those mentioned above are discussed in U.S. Pat. No. 4,131,882 issued December, 1978 to Hollabaugh, et al., U.S. Pat. No. 4,176,395 issued November, 1979 to Evelyn-Vecre, et al., U.S. Pat. No. 4,209,131 issued June, 1980 to Barash, et al., U.S. Pat. No. 5,048,755 issued September, 1991 to Dodds and U.S. Pat. No. 5,839,658 issued November, 1998 to Sarver. The problem with the above mentioned irrigation systems is that either a wire, separate from the power wire, is used to transmit the encoded message from the irrigation controller to the solenoid/valve unit or if the encoded message is transmitted over the power line the alternating-current power is significantly affected to permit the sending of the encoded message.
What is needed is a simplified irrigation valve controller that can operate off of two wires, and where the transmission of the control data only minimally affects the current to the valves.
The following invention provides an irrigation controller that provides a current to operate an irrigation valve assembly and superimposes a data stream on the current. The current may be either alternating current or direct current. Preferably the current is transmitted over a two-wire link. Alternatively, the current may be transmitted over less than or more than a two-wire link.
In a preferred embodiment of the present invention the irrigation valve assembly includes a decoder, a solenoid and an irrigation valve. It is contemplated that the decoder will communicate bi-directionally with the irrigation controller.
It is contemplated that the data stream will be an encoded control signal that is sent at a rate greater than 1 byte per second. Additionally, the encoded control signal may be sent at a rate greater than or less than the rate of the current.
Various objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention, along with the accompanying drawings in which like numerals represent like components.